Word
fly
US/ˈfɫaɪ/
UK/flˈaɪ/
Irregular verb
Forms
Infinitive
fly
Past
flew
Past participle
flown
Definitions
01to move through the air
A1 · Beginner
v. to move through the air using wings or an aircraft.
v. to move through the air or space under one's own power or by means of an aircraft. Intransitive in this sense.
“The birds fly south every year when the weather starts to get cold.”
“The pilot managed to fly the damaged aircraft through the storm, landing safely despite the failing engine.”
Pitfall
The bird has flied away.
The bird has flown away.
The verb 'fly' is irregular: fly, flew, flown.
02to move very fast
B1 · Intermediate Informal
v. to move or go somewhere very quickly.
v. to move, pass, or progress with great speed or haste.
“I have to fly or I will be late for my doctor's appointment.”
“Time seemed to fly during the summer holidays, leaving the students unprepared for the sudden return to their studies.”
Teaching tip
Often used with 'time' to express how quickly a period has passed.
03to be accepted
B2 · Upper Intermediate Informal
v. to be successful or accepted by other people.
v. to be valid, acceptable, or successful in a particular context.
“That excuse about your dog eating your homework just won't fly with the teacher.”
“The board of directors made it clear that the proposed budget cuts simply would not fly in the current economic climate.”
Usage
Usually used in the negative to mean a plan or excuse will not be believed.
Antonyms
04to display a flag
B1 · Intermediate
v. to show a flag by hanging it from a pole.
v. to display a flag or banner from a pole or mast. Transitive use.
“The ship was flying a red flag to warn other boats of the danger.”
“Every government building in the capital was required to fly the national colours during the independence celebrations.”
Antonyms
05the insect
A2 · Elementary Countable noun zoology
n. a small insect with two wings that often makes a buzzing sound.
n. any two-winged insect of the order Diptera, specifically the common housefly.
“A fly was buzzing around the kitchen while I was trying to cook dinner.”
“The biologist observed the fly under the microscope to study the intricate structure of its compound eyes.”
Usage
The plural is 'flies'.
Synonyms
06trousers opening
B1 · Intermediate Countable noun
n. the opening at the front of a pair of trousers that uses a zipper or buttons.
n. an opening at the crotch of a pair of trousers, typically closed by a zipper or buttons and covered by a fabric flap.
“He realized his fly was open just as he walked onto the stage.”
“The tailor carefully stitched the fly of the bespoke trousers to ensure the buttons remained hidden behind the silk placket.”
Usage
Often used in the plural 'flies' in British English, but singular 'fly' in American English.
07fishing lure
C1 · Advanced Countable noun fishing Technical
n. a fake insect used as bait to catch fish.
n. an artificial fishing lure made of silk, feathers, or similar material to resemble an insect.
Español:mosca
“He spent the afternoon choosing the right fly to catch trout in the river.”
“Experienced anglers often tie their own flies, meticulously matching the local insect population to increase their chances of a strike.”
08stylish
C1 · Advanced Slang · Informal
adj. looking very cool, stylish, or attractive.
adj. stylish, fashionable, or physically attractive. Primarily used in urban contexts.
“Those new sneakers you bought are looking really fly.”
“He showed up to the party looking fly in a vintage leather jacket and designer sunglasses.”
Teaching tip
This term was very popular in 1990s hip-hop culture; it is still used but can feel slightly dated to some speakers.
Etymology
From Middle English flye, flie, from Old English flȳġe, flēoge (“a fly”), from Proto-West Germanic fleugā, from Proto-Germanic fleugǭ (“a fly”), from Proto-Indo-European *plewk- (“to fly”). Cognate with Scots flee, Saterland Frisian Fljooge, Dutch vlieg, German Low German Fleeg, German Fliege, Danish flue, Norwegian Bokmål flue, Norwegian Nynorsk fluge, Swedish fluga, Icelandic fluga.
From Middle English flien, from Old English flēogan, from Proto-West Germanic fleugan, from Proto-Germanic fleuganą, from Proto-Indo-European plewk- (plew-k-, “to fly”), enlargement of *plew- (“flow”). Compare Etymology 1. See also Saterland Frisian fljooge, Dutch vliegen, Low German flegen, German fliegen, Danish flyve, Norwegian Nynorsk flyga; also Lithuanian plaũkti ‘to swim’). More at flee and flow.
From Middle English flye (“flying, flight”), from Old English flyge (“flying, flight”), from Proto-Germanic *flugiz.
Uncertain; probably from the verb or noun.
Related to German Flügel (“a wing”), Dutch vleugel (“a wing”), Swedish flygel (“a wing”).
Etymology adapted from Wiktionary, available under CC BY-SA 4.0.
Word family
VERB
Related words
Idioms
01. fly blind
02. fly by
03. fly by the seat of one's pants
06. fly low
07. fly off
Show all 26
11. fly on the wall
14. fly solo
15. fly the flag
18. go fly a kite
19. hurt a fly
20. let fly
21. on the fly
22. pigs can fly
23. pigs might fly
24. straighten up and fly right
25. the feathers fly
26. when pigs fly
Domains
- Exam level
- CambridgeCambridgeCambridge English QualificationsThe exam suite from Cambridge University Press & Assessment, from A1 Movers up to C2 Proficiency. The benchmark names double as CEFR labels.A2 KeyIELTSIELTSInternational English Language Testing SystemThe 0–9 band test co-owned by the British Council, IDP, and Cambridge. Used for university entry, work, and migration.3.0–4.0TOEFL iBTTOEFL iBTTest of English as a Foreign Language, Internet-Based TestETS's academic English test, the standard route for US university admissions. Scored 0–120, with a 1–6 scale since 2026.1–6 scale: 2.0–2.524–43TOEICTOEICTest of English for International CommunicationETS's workplace English test, big in Japan and Korea. Listening & Reading scores 10–990 and tops out at C1.225–549
- Frequency
- Common
- Level
- A2 · ElementaryOxford
- Updated
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QR code
englishreference.com/q/fly
Traducciones: Kaikki.org (Wiktionary), CC BY-SA 4.0